Mongoose field not required but unique

Question

I have an email field set as unique, but it is not required.

The problem is that if the user does not enter anything Mongoose puts "null" in it. This causes duplicates because every user that does not enter the email field will have "null" assigned to it.

What is the standard practice to avoid this?

Thanks

How is the default value to be calculated? What sort of data type is the field? — PeterVC, Jun 19 '17 at 20:46
it's a string. I guess I could put a random number in string form in it? — Nicola Pedretti, Jun 19 '17 at 20:48

score 18 · Accepted Answer · answered Jun 19 '17 at 23:17

18

Use a sparse unique index

If a document does not have a value for a field, the index entry for that item will be null in any index that includes it. Thus, in many situations you will want to combine the unique constraint with the sparse option. Sparse indexes skip over any document that is missing the indexed field, rather than storing null for the index entry.

db.collection.createIndex( { a: 1, b: 1 }, { unique: true, sparse: true } )

More information: https://docs.mongodb.com/v3.0/tutorial/create-a-unique-index/

answered Jun 19 '17 at 23:17

Sam Quinn

3,310
1
16
11

1

Thanks man! this is what i was looking for – Nicola Pedretti Jun 19 '17 at 23:18
2

`MongoDB cannot create a unique index on the specified index field(s) if the collection already contains data that would violate the unique constraint for the index.` – Pavindu Apr 14 '20 at 11:41

Mongoose field not required but unique

1 Answers1

Use a sparse unique index